在移动端不同设备的dpr(物理像素比)不一样,导致1px的逻辑像素渲染出不同的粗细,比如dpr=3时1个逻辑像素点(1px)=3个物理像素点 这不是我们想要的 我们要在所有不同dpr的设备上显示1px的效果保持一致
最佳实践: antd的伪元素+transform缩放实现:
src/styles/common.scss:
// 设置边框的公共方法
@mixin scale-hairline-common($color, $top, $right, $bottom, $left) {
content: '';
position: absolute;
display: block;
z-index: 1;
top: $top;
right: $right;
bottom: $bottom;
left: $left;
background-color: $color;
}
// 添加边框
/*
用法:
// 导入(已全局导入 这步可省略)
@import '@scss/hairline.scss';
// 在类中使用
.a {
@include hairline(bottom, #f0f0f0);
}
*/
@mixin hairline($direction, $color: #000, $radius: 0) {
position: relative; // 父盒子相对定位 否则伪元素会跑到别的定位元素去
@if $direction == top {
border-top: 1px solid $color;
// min-resolution 用来检测设备的最小像素密度
/**
因为dpr不一样导致1px所占的物理像素个数不一样导致线条变粗 根据像素比等比缩放
如果设备像素比不为1则用scale等比缩放到1 否则直接设置border为1px
*/
@media (min-resolution: 2dppx) {
border-top: none;
&::before {
@include scale-hairline-common($color, 0, auto, auto, 0);
width: 100%;
height: 1px;
transform-origin: 50% 50%;
transform: scaleY(0.5);
@media (min-resolution: 3dppx) {
transform: scaleY(0.33);
}
}
}
} @else if $direction == right {
border-right: 1px solid $color;
@media (min-resolution: 2dppx) {
border-right: none;
&::after {
@include scale-hairline-common($color, 0, 0, auto, auto);
width: 1px;
height: 100%;
background: $color;
transform-origin: 100% 50%;
transform: scaleX(0.5);
@media (min-resolution: 3dppx) {
transform: scaleX(0.33);
}
}
}
} @else if $direction == bottom {
border-bottom: 1px solid $color;
@media (min-resolution: 2dppx) {
border-bottom: none;
&::after {
@include scale-hairline-common($color, auto, auto, 0, 0);
width: 100%;
height: 1px;
transform-origin: 50% 100%;
transform: scaleY(0.5);
@media (min-resolution: 3dppx) {
transform: scaleY(0.33);
}
}
}
} @else if $direction == left {
border-left: 1px solid $color;
@media (min-resolution: 2dppx) {
border-left: none;
&::before {
@include scale-hairline-common($color, 0, auto, auto, 0);
width: 1px;
height: 100%;
transform-origin: 100% 50%;
transform: scaleX(0.5);
@media (min-resolution: 3dppx) {
transform: scaleX(0.33);
}
}
}
} @else if $direction == all {
border: 1px solid $color;
border-radius: $radius;
@media (min-resolution: 2dppx) {
border: none;
&::before {
content: '';
position: absolute;
left: 0;
top: 0;
width: 200%;
height: 200%;
border: 1px solid $color;
border-radius: $radius * 2;
transform-origin: 0 0;
transform: scale(0.5);
box-sizing: border-box;
pointer-events: none;
@media (min-resolution: 3dppx) {
width: 300%;
height: 300%;
transform: scale(0.33);
border-radius: $radius * 3;
}
}
}
}
}
// 移除边框
@mixin hairline-remove($position: all) {
@if $position == left {
border-left: 0;
&::before {
display: none !important;
}
} @else if $position == right {
border-right: 0;
&::after {
display: none !important;
}
} @else if $position == top {
border-top: 0;
&::before {
display: none !important;
}
} @else if $position == bottom {
border-bottom: 0;
&::after {
display: none !important;
}
} @else if $position == all {
border: 0;
&::before {
display: none !important;
}
&::after {
display: none !important;
}
}
}